Wafer shipping box and wafer transportation method

ABSTRACT

A wafer shipping box for carrying a number of wafers is provided. The wafer shipping box includes a main body, a cover and a sealing element. The cover can join up with the main body to seal off wafers inside the wafer shipping box. A vent hole is set up on either the body or the cover. The sealing element is used to seal or open the vent hole. Through the sealing element, the vent hole can be sealed so that micro-particles and corrosive gases are prevented from contaminating the wafers and the interior of the wafer box during shipment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wafer shipping box and wafer transportation method. More particularly, the present invention relates to a wafer shipping box and wafer transportation method that can prevent micro-particles and corrosive gases from contaminating the wafers.

2. Description of the Related Art

Due to the many breakthroughs in semiconductor fabrication techniques in recent years, the level of integration in semiconductor devices has been increasing while the line width of interconnecting wires has been reducing constantly. With a higher level of integration and a narrower line width, semiconductor manufactures are able to pack more devices within a single wafer and lower production cost. However, as each silicon wafer contains lots of devices intricately connected together through fine wires, minute amount of contaminants (for example, micro-particles, metallic ions, organic material and so on) may produce defects somewhere in the integrated circuits and render them unusable. This can be a leading cause for a drop in yield and lost to manufacturers.

One of the major source of contaminants is the air. Micro-particles suspended in the air may deposit on a wafer and ultimately lead to an electrical failure. Inside a manufacturing plant, the wafers are usually handled inside a clean room so that possible damage to the wafers is minimized. However, the wafers can be seriously contaminated if they are handled without appropriate protection during transportation. To prevent wafer contamination in transition, the wafers are often housed within a wafer shipping box so that the wafers are isolated from external contaminants.

FIG. 1 is a schematic cross-sectional view of a conventional wafer shipping box. As shown in FIG. 1, the wafer shipping box 100 includes a main body 120, a cover 140 and a vent hole 160. A plurality of wafer support structures 122 is set up within the main body 120 for accommodating a plurality of wafers 130. The cover 140 has a latching element 142 for joining with the main body 120 so that the two are combined to form an integrated unit. The vent hole 160 is disposed on the cover 140. The vent hole 160 has a filtering device 162 for screen off micro-particles from the air. In addition, the vent hole 160 is designed to balance the air pressure inside and outside the wafer shipping box 100 and prevent any difficulty in opening up the wafer box 100 due to a differential pressure between the interior and exterior of the wafer box.

However, the vent hole 160 of the conventional wafer box 100 still permits the entrance of some micro-particles into the interior of the box 100 and contaminates the wafers 130. Although the vent hole 160 has a built-in filtering device 162, the filtering device 162 has a fixed capacity for trapping micro-particles. Once the filtering device 162 has been saturated, some of the micro-particles may drop into the box 100 due to gravity or when the box is slightly shaken (during transportation) and lead to wafer contamination.

In addition, the vent hole 160 is not designed to filter any corrosive gases or ions such as sulfate ions (SO₄ ²⁻) and chlorine ions (Cl⁻) that are normally absent in a clean room. When these gases and ions enter the wafer shipping box, the batch of wafers inside the box may be contaminated. Sometimes, the wafer box is wrapped inside a sealing bag as a means of isolation. If the sealing bag should produce some gaseous contaminants due to out-gasing, the interior of the box and the wafer inside the box may also be contaminated.

SUMMARY OF THE INVENTION

Accordingly, a objective of the present invention is to provide a wafer shipping box capable of carrying wafers and preventing the wafers in the interior of the box from being contaminated.

At least a objective of the present invention is to provide a method of transporting wafers that can provide a high degree of cleanliness for the wafers and wafer carrier in transition.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a wafer shipping box for holding a plurality of wafers. The wafer box comprises a main body, a cover, a vent hole and a sealing element. The main body has a plurality of wafer support structures for supporting wafers. The cover can latch onto the main body so that the wafers are enclosed within the box. The vent hole is set up on the main body or the cover. The sealing element is used to seal the vent hole or open the vent hole.

According to one embodiment of the present invention, the wafer shipping box is adapted to carry a multiple of wafers each having a wafer diameter such as 12 inches. In addition, the sealing element can be implemented in several ways. For example, the sealing element can be a plastic tape, a sheath, a cap or a plug. Moreover, the vent hole and the sealing element can be engaged together in a number of ways including screwing or sliding into each other.

The wafer shipping box of the present invention uses a sealing element to isolate the interior of the wafer box from the external environment. Hence, contaminating substances such as foreign micro-particles and corrosive gases are precluded from the interior of the wafer box.

The present invention also provides a method of transporting wafers. The method includes transferring wafers into the interior of a wafer shipping box in a first environment. The wafer box has a vent hole. After sealing the vent hole with a sealing element in the first environment, the wafer box is transported from the first environment to a second environment. Before opening the wafer box, the sealing element on the vent hole is removed so that the pressure inside and outside the wafer box is equalized. Finally, the wafer box is opened and the wafers are accessed.

In the aforementioned wafer transportation method, the sealed wafer shipping box prevents any external contaminants from getting to the wafers during transportation and hence maintains a high degree of cleanliness for the wafers inside the box.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic cross-sectional view of a conventional wafer shipping box.

FIG. 2 is a schematic cross-sectional view of a wafer shipping box according to the present invention.

FIGS. 3A through 3D shows several types of sealing elements for the wafer box in FIG. 2.

FIG. 4 is a flow chart showing the steps for implementing the wafer transportation method according to the prevent invention.

FIGS. 5A through 5D shows the configurations of the wafer shipping box when the wafer transportation method of the present invention is deployed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

FIG. 2 is a schematic cross-sectional view of a wafer shipping box according to the present invention. As shown in FIG. 2, the wafer shipping box 200 comprises a main body 220, a cover 240 and a sealing element 280. The main body 220 has a plurality of wafer support structures for holding a plurality of wafers 230. In one embodiment of the invention, the wafer 230 has a 12-inch diameter, for example.

The cover 240 can latch onto the main body 220. As shown in FIG. 2, the cover 240 and the main body 220 are engaged together through a latching element 242 set up on the cover 240, for example. Through the engagement of the main body 220 and the cover 240, the wafers 230 are enclosed inside the wafer box 200. Alternatively, the cover 240 and the main body 220 are engaged together through a latching element 242 set up on the main body 220 instead.

A vent hole 260 is set up on either the main body 220 or the cover 240, or is set up on the main body 220 and the cover 240. In the present embodiment, the vent hole 260 is set up on the cover 240. The vent hole 260 may further comprise a filtering device 262 that permits the passage of air and prevents unwanted external contaminants such as micro-particles and corrosive gases from entering into the wafer box 200. For example, the filtering device 262 contains a porous filler material (such as activated carbon) for trapping micro-particles and scrubbing corrosive gases. Through the filtering device 262, micro-particles and corrosive gases are blocked or trapped by the filler material.

The sealing element 280 is used for sealing or opening the vent hole 260 so that the interior wafer shipping box 200 is thoroughly isolated from the external environment.

FIGS. 3A through 3D shows several types of sealing elements for the wafer box in FIG. 2. In a first embodiment as shown in FIG. 3A, the sealing element is a piece of plastic tape 280 a that completely seals the vent hole 260. The plastic tape 280 a is torn off when the wafer box 200 reaches its destination.

In a second embodiment as shown in FIG. 3B, the sealing element 280 is a sheath 280 b fabricated using a soft and elastic material. The sheath 280 a can be stretched and pulled over the vent hole 260. The soft sheath 280 b is removed when the wafer box 200 reaches its destination. After the air pressure inside and outside the wafer box 200 has been equalized, the wafer box 200 can be opened to retrieve the wafers 230.

In a third embodiment as shown in FIG. 3C, the sealing element 280 is a cap 280 c. The cap 280 c is screwed onto the vent hole 260, for example. In this case, the vent hole 260 has externally screw threads while the cap 280 c has matching internal screw threads. The vent hole 260 is sealed when the cap 280 c is screwed onto the vent hole 260. Obviously, the cap 280 c may seal off the vent hole 260 by sliding over it.

In a fourth embodiment as shown in FIG. 3D the sealing element is a plug 280 d. The plug 280 d is screwed onto the vent hole 260, for example. In this case, the vent hole 260 has internal screw threads while the plug 280 d has matching external screw threads. The vent hole 260 is sealed when the plug 280 d is screwed onto the vent hole 260. Obviously, the plug 280 c may seal off the vent hole 260 by squeezing into the hole.

In FIGS. 3B through 3B, the sealing element 280 is linked to the vent hole 260 through a connecting element 270 so that the sealing element 280 and the wafer box 200 together form an integrative unit. In one embodiment of the present invention, the connecting element 270 is a piece of wire, for example.

In the aforementioned wafer shipping box, a sealing element is deployed to isolate the interior of the wafer box from the external environment and prevent any micro-particles or corrosive gases from entering and contaminating the stored wafers inside the box.

The present invention also provides a method of transporting wafers. FIG. 4 is a flow chart showing the steps for implementing the wafer transportation method according to the prevent invention. FIGS. 5A through 5D shows the configurations of the wafer shipping box when the wafer transportation method of the present invention is deployed. In step 400 as shown in FIG. 4, a plurality of wafers 230 is placed inside the main body of a wafer shipping box in a first environment 201 such as the interior of a clean room or a fabricating station. A wafer box cover is latched on the main body so that the wafers 230 are packed inside the wafer box in a configuration as shown in FIG. 5A.

In step 410, the vent hole 260 on the wafer box 220 is sealed using a sealing element 280 to produce a configuration as shown in FIG. 5B. Thereafter, the wafers 230 are transported from the first environment 201 to a second environment 202 such as another clean room or another wafer reaction chamber.

In step 420, the sealing element 280 is lifted from the vent hole 260 so that the air pressure inside the wafer box 200 equalizes with the pressure outside the wafer box 200 in the second environment 202. The configuration of the wafer box 200 is shown in FIG. 5C.

In step 420, the cover 240 of the wafer box 200 is removed to retrieve wafers 230 from the wafer box 200. The final configuration of the wafer box 200 is shown in FIG. 5D.

In the aforementioned method of transporting wafers using a sealed wafer shipping box is able to isolate the wafers against any environmental contaminants during the transportation and ensure a high degree of cleanliness of the wafer inside the box.

In summary, the wafer shipping box and wafer transportation method of the present invention has at least the following advantages:

1. The sealing of a wafer box with a sealing element before transportation isolates the wafers stored inside the box from possible environmental contaminants in transition.

2. The vent hole on either the main body or the cover of the shipping box not only has micro-particle filtering capability, but can be used for equalizing the pressure differential between the inside and the outside the wafer box.

3. By sealing the vent hole with a sealing element, the wafers inside the wafer box are protected against possible contamination during wafer transportation.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A wafer shipping box for carrying a plurality of wafers, comprising: a main body having a plurality of wafer supporting structures for carrying wafers; a cover for engaging with the main body so that the wafers are enclosed, wherein a vent hole is disposed on the main body or the cover; and a sealing element for sealing and unsealing the vent hole.
 2. The wafer box of claim 1, wherein the wafers comprise 12-inch diameter wafers.
 3. The wafer box of claim 1, wherein the box further comprises a filtering device disposed on the vent hole.
 4. The wafer box of claim 1, wherein the sealing element comprises a piece of plastic tape.
 5. The wafer box of claim 1, wherein the sealing element comprises a sheath.
 6. The wafer box of claim 1, wherein the sealing element comprises a cap.
 7. The wafer box of claim 6, wherein the vent hole has external screw threads and the cap has matching internal screw threads so that the cap can be screwed into the vent hole to seal off the wafer box.
 8. The wafer box of claim 1, wherein the sealing element comprises a plug.
 9. The wafer box of claim 8, wherein the vent hole has internal screw threads and the plug has external screw threads so that the plug can be screwed into the vent hole to seal off the wafer box.
 10. The wafer box of claim 1, wherein the sealing element further comprises a connective line that links the sealing element to the vent hole.
 11. A method of transporting wafer, comprising the steps of: placing a plurality of wafers into a wafer shipping box in a first environment, wherein the wafer shipping box has a vent hole; sealing the vent hole with a sealing element while the wafer shipping box is still in the first environment; transporting the wafer shipping box from the first environment to a second environment; and unsealing the sealing element and opening the wafer shipping box after the air pressure between the interior and exterior of the box are equalized.
 12. The method of claim 11, wherein the wafers comprises 12-inch diameter wafers.
 13. The method of claim 11, wherein the wafer shipping box further comprises a filtering device disposed on the vent hole.
 14. The method of claim 11, wherein the sealing element comprises a piece of plastic tape.
 15. The method of claim 11, wherein the sealing element comprises a sheath.
 16. The method of claim 11, wherein the sealing element comprises a cap.
 17. The method of claim 16, wherein the vent hole has external screw threads and the cap has matching internal screw threads so that the cap can be screwed into the vent hole to seal off the wafer shipping box.
 18. The method of claim 11, wherein the sealing element comprises a plug.
 19. The method of claim 18, wherein the vent hole has internal screw threads and the plug has matching external screw threads so that the plug can be screwed into the vent hole to seal off the wafer shipping box.
 20. The method of claim 11, wherein the wafer shipping box further comprises a connective line linking the sealing element to the vent hole. 